Well-watered plants transpire more during sunny and windy days than in cool and calm mornings. Comment.

3

(a)

Photosynthesis needs constant supply of water. But transpiration can hamper this supply. How do plants of desert area manage to get sufficient water in spite of faster transpiration?

3

(a)

How does the absorption and loss of potassium ions in the guard cells bring about the opening and closing of stomata?

3

(a)

What are the two types of interaction of water molecules that allow water to travel upwards in the plants? What other physical process aids in water transport to the top of the trees? Explain.

3

(a)

Organic substances are translocated in upward and downward directions through phloem. Answer the following
(i) What is the effect of blocking the phloem?
(ii) What do you find in chemical analysis of phloem sap?

3

(a)